Cancer is the second leading cause of death worldwide, accounting for 8.2 million deaths in 2012. It is expected that annual cancer cases will rise from 14 million in 2012 to 22 million within the next two decades.
Conventional treatments for cancer using radiation or chemotherapeutic drugs target rapidly proliferating cells and induce such cells to undergo apoptosis. Most chemotherapeutic agents exhibit some degree of toxicity toward normal cells at therapeutic doses, causing undesired side effects that may be dose limiting, thereby reducing the usefulness of the drugs. Furthermore, these traditional methods of treatment are not successful in treating many types of cancers, particularly those that are resistant to apoptotic stimuli. Since the cytotoxic agents in most chemotherapeutic drugs act primarily through p53-dependent induction of apoptosis, and p53 is often mutated in cancers cells, resistance to chemotherapy is often observed in cancer patients. As a consequence, there is an ongoing need for new therapeutic agents that are more effective in treating cancers.